Methods of treating a subterranean formation with shrinkable fibers

Abstract

Methods of treating a subterranean formation are disclosed that include introducing a treatment fluid including thermally shrinkable fibers and a particulate material into a subterranean formation via a wellbore, adjusting at least one parameter of the treatment fluid to trigger the association of the thermally shrinkable fibers, and forming a porous pack including a network of shrunken fibers by applying heat sufficient to raise the temperature of the thermally shrinkable fibers to a temperature at or above a shrinking initiation temperature of the thermally shrinkable fibers.

1 . A method for treating a subterranean formation comprising:
 introducing a treatment fluid including thermally shrinkable fibers and a particulate material into a subterranean formation via a wellbore;   thermally triggering a mechanical association of the thermally shrinkable fibers; and   
       after triggering the mechanical association of the thermally shrinkable fibers, forming a porous pack comprising a network of shrunken fibers by conducting a shrinking process including applying heat sufficient to raise the temperature of the thermally shrinkable fibers to a temperature at or above a shrinking initiation temperature of the thermally shrinkable fibers; wherein at least a portion of the shrunken fibers are made to assume a geometry in which the shrunken fiber is hooked on one or both ends as a result of the shrinking process. 
     
     
         2 . The method of  claim 1 , further comprising preventing a flowback of one or more particles through the wellbore during a production of formation fluids in a fracturing operation, wherein one or more particles are selected from the group consisting of proppant, natural formation particulates and fines. 
     
     
         3 . The method of  claim 1 , wherein the shrunken fibers have an average length, measured at a temperature at or above a shrinking initiation temperature, that is about 80 or less percent of the average length of the thermally shrinkable fibers measured at 25° C. and pressure of 1 atmosphere. 
     
     
         4 . The method of  claim 1 , wherein the treatment fluid further comprises at least one thermally non-shrinkable fiber that forms a covalent and/or non-covalent association with the thermally shrinkable fiber before the porous pack is formed. 
     
     
         5 . The method of  claim 1 , wherein at least a portion of the particulate material is proppant. 
     
     
         6 . The method of  claim 1 , wherein the shrunken fiber has a length in the range of from about 0.3 mm to about 45 mm. 
     
     
         7 . The method of  claim 1 , wherein the thermally shrinkable fibers are present in the treatment fluid in an amount in the range of from about 0.3% to about 2.5% by weight of the particulate material. 
     
     
         8 . The method of  claim 1 , wherein the shrinkage initiating temperature of the thermally shrinkable fibers is in the range of from about 40° C. to about 180° C. 
     
     
         9 . The method of  claim 1 , wherein the shrunken fibers are present in the porous pack in an amount in the range of from about 0.3 to about 2.5% by weight of the porous pack 
     
     
         10 . The method of  claim 1 , wherein an average diameter of the thermally shrinkable fibers is in the range of from about 10 microns to about 100 microns. 
     
     
         11 . The method of  claim 1 , wherein the thermally shrinkable fibers are capable of shrinking to a length that is in the range of from about 60% to about 90% of their initial length as measured at 25° C. and pressure of 1 atmosphere. 
     
     
         12 . The method of  claim 1 , wherein at least a portion of the thermally shrinkable fibers have a bi-component structure. 
     
     
         13 . The method of  claim 1 , wherein at least a portion of the thermally shrinkable fibers are bi-component thermally shrinkable fibers with a core/sheath coaxial structure. 
     
     
         14 . The method of  claim 1 , wherein at least a portion of the thermally shrinkable fibers are bi-component thermally shrinkable fibers with a core/sheath coaxial structure, where the sheath is an amorphous polymer. 
     
     
         15 . The method of  claim 1 , wherein at least a portion of the thermally shrinkable fibers are bi-component thermally shrinkable fibers with a core/sheath coaxial structure, where the sheath is an amorphous polymer and the core is selected from a crystalline polymer or a semi-crystalline polymer. 
     
     
         16 . The method of  claim 1 , wherein the thermally shrinkable fibers shrink to form the shrunken fibers without degrading. 
     
     
         17 . The method of  claim 1 , wherein
 the thermally shrinkable fibers shrink to form the shrunken fibers without degrading, and   the shrunken fibers are stable in the subterranean formation.   
     
     
         18 . The method of  claim 1 , wherein the thermally shrinkable fibers are formed from a polymer selected from the group consisting of polystyrene and poly(methyl methacrylate). 
     
     
         19 . A method for treating a subterranean formation comprising:
 introducing a treatment fluid including thermally shrinkable fibers and a particulate material into a subterranean formation via a wellbore;   thermally triggering a mechanical association of the thermally shrinkable fibers; and   
       after triggering the mechanical association of the thermally shrinkable fibers, forming a porous pack comprising a network of shrunken fibers by applying heat sufficient to raise the temperature of the thermally shrinkable fibers to a temperature at or above a shrinking initiation temperature of the thermally shrinkable fibers; wherein
 apart from shrinking, the thermally shrinkable fibers are stable in the subterranean formation, and 
 the shrunken fibers are stable in the subterranean formation. 
 
     
     
         20 . The method of  claim 19 , wherein the thermally shrinkable fibers are formed from a polymer selected from the group consisting of polystyrene and poly(methyl methacrylate).